<?php

/**
 * Maikuro CMS
 *
 * LICENSE:
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * The license is bundled with this package in the file LICENSE.txt.
 * You may also obtain a copy of the License at this URL:
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @copyright  Copyright (c) 2010, Jonathan Hedrén
 * @author     Jonathan Hedrén <jonathan.hedren@gmail.com>
 * @license    http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 */

class EventHandler
{
    /**
     *
     * @var array
     */
    protected $observers = array();
    
    /**
     * 
     * @var array
     */
    protected $updateMethods = array();

    /**
     *
     * @param string $event
     * @param mixed $args
     * @return EventHandler
     */
    public function dispatchEvent($event, $args = null)
    {
        if (isset($this->observers[$event])
            && is_array($this->observers[$event])) {
                foreach ($this->observers[$event] as $index => $observer) {
                    $updateMethod = $this->updateMethods[$event][$index];
                    $observer->$updateMethod($event, $args);
                }
        }
        return $this;
    }

    /**
     *
     * @param string $event
     * @param IObserver $observer
     * @todo updateMethodName and priority args
     * @return EventHandler
     */
    public function observeEvent($event, $observer, $updateMethodName = null/*, $priority = null*/)
    {
        if ($updateMethodName == null && !$observer instanceof IObserver) {
            throw new Exception('An event observer must implement the IObserver interface if no $updateMethodName is given.');
        }
        
        if (!isset($this->observers[$event])) {
            $this->observers[$event] = array();
        }
        $this->observers[$event][] = $observer;
        
        if (!isset($this->updateMethods[$event])) {
            $this->updateMethods[$event] = array();
        }
        if ($updateMethodName == null) {
            $updateMethodName = 'update';
        }
        $this->updateMethods[$event][] = $updateMethodName;
        return $this;
    }

    /**
     *
     * @param string $event
     * @return array|null
     */
    public function getEventObservers($event)
    {
        return isset($this->observers[$event]) ? $this->observers[$event] : null;
    }
}